Chemical Reactions Test Review

How many oxygen atoms are present in the following? 
4Ca(OH)₂

• 4
• 6
• 8
• 1

Tags

NGSS.MS-PS1-1

Why must we balance chemical equations? 

• Our teacher said so
• to abide by the law of conservation of energy
• to abide by the law of conservation of mass

Tags

NGSS.HS-PS1-7

 Fill in the blank to balance the chemical equation. 
2KI  +  ____Cl₂ →  2KCl  +  I₂

• 1
• 2
• 3
• 4

What coefficient should go in the blank space to balance the chemical equation? 
2Al  +____  HCl   →    2AlCl₃  +  3H2

• 2
• 4
• 3
• 6

Tags

NGSS.HS-PS1-7

Balance this equation ​ (a)   N₂ + ​ (b)   H₂ --> ​ (c)   NH₃

• 1
• 3
• 2

According to the Law of Conservation of Mass (Matter), Matter cannot be ​ (a)   or ​ (b)   , it can only be ​ (c)   . This means however many atoms of an element we have before a reaction must be ​ (d)   to the number after a reaction.

• created
• destroyed
• changed
• equal

Tags

NGSS.HS-PS1-7

What is the little number after an element in a chemical equation called.
Example: H₂

• Coefficient 

• Subscript

• Atom

• Equation

Which of the following equations are correctly balanced?

• 12CO₂ +H₂O --> C₆H₁₂O₆ + O₂

• CO₂ + 9H₂O --> C₆H₁₂O₆ + O₂

• CO₂ + H₂O --> 3C₆H₁₂O₆ + O₂

• 6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

Which one is an element?

• Co
• CO
• CO₂
• CO₃^-2

Tags

NGSS.HS-PS1-1

Is the compound in the pink box a Reactant or a Product?

• Reactant

• Product